Injuries: Former Chicago Bears quarterback Jim McMahon, pictured in 1988, has revealed he suffers from memory loss after repeated blows to the head

A former star quarterback as revealed he now suffers from memory loss as a result of repeated blows to the head during his NFL career.

Super Bowl winner Jim McMahon, who played for the Chicago Bears between 1982 and 1988, has said during his playing days he would just take an aspirin after a heavy hit and go back on the field.

Mr McMahon, who was known for his head first baseball-style slides while running the ball, is now trying to raise money for brain research after 15 seasons in the NFL.

The 51-year-old told the Chicago Tribune: 'My memory's pretty much gone. There a are a lot of times when I walk into a room and forget why I walked in there.

'I'm going through some studies right now and I am going to do a brain scan.

'It's unfortunate what the game does to you.'

He added that when he played, quarterbacks were not as well protected as they are today.

'Back then, it was just tape an aspirin to your helmet and you go back in.

'I've worked with some neurosurgeons and it's a very serious thing, man.'

Mr McMahon, who won the Super Bowl with the Bears in 1986, also played for the Green Bay Packers, Minnesota Viking and Philadelphia Eagles.

He is the latest high-profile case of football players suffering brain injuries as a result of collisions during games.

In April, 21-year-old Pennsylvania football captain Owen Thomas hanged himself after an 'uncharacteristic emotional collapse'.

A post mortem found that his brain tissue showed early signs of CTE - chronic traumatic encephalopathy - which can lead to poor decision-making, impaired memory, erratic behaviour and suicide.

There have been several cases among veteran NFL players, including Chris Henry, 26, a Cincinnati Bengals wide receiver who died in December during a domestic dispute in which he appeared to jump from the back of a moving pickup truck, and Philadelphia Eagle Andre Waters, who killed himself at his home in 2006.

And last month calls were made to tighten safety rules after a Rutgers College student was left without feeling below his neck following a collision with another player.

Eric LeGrand, 20, suffered a serious spinal injury that could leave him paralysed after a clash of heads with an opposing player.

The NFL, which has tried for years to play down the link between hard tackles and brain damage, has since introduced a series of fines for players who commit head-clashing tackles.